Prototype - Form.Element clear() 方法
此方法清除文本输入的内容。
语法
formElement.clear();
返回值
它返回一个 HTML 元素。
示例
此代码设置一个文本字段，使其在第一次获得焦点时清除其内容。
<html>
<head>
<title>Prototype examples</title>
<script type = "text/javascript" src = "/javascript/prototype.js"></script>
<script>
function showResult() {
$('username').onfocus = function() {
// 如果已经清除，则不执行任何操作
if (this._cleared) return
// 否则此处清除
this.clear()
this._cleared = true
}
}
</script>
</head>
<body onload = "showResult();">
<p>Focus on username to see the result:</p>
<br />
<form id = "example" action = "#" onsubmit = "return false">
<fieldset>
<legend>User info</legend>
<div>
<label for = "username">Username:</label>
<input name = "username" id = "username" value = "Sai" type = "text">
</div>
<div>
<label for = "age">Age:</label>
<input name = "age" id = "age" value = "23" size = "3" type = "text">
</div>
<div>
<label for = "hobbies">Your hobbies :</label>
<select name = "hobbies" id = "hobbies" multiple = "multiple">
<option>coding</option>
<option>swimming</option>
<option>hiking</option>
<option>drawing</option>
</select>
</div>
</fieldset>
</form>
</body>
</html>
输出
prototype_form_management.html
